Each time the foot of a runner contacts the ground, considerable shock force is transmitted through the shoe to the wearer's foot. After a time, this shock force can result in fatigue and discomfort. Various shock-absorbing sole materials have been utilized to absorb at least a portion of the shock and to thereby overcome this problem.
Immediately following foot contact with the ground, the foot tends to roll about its long axis towards the inside, or medial side. This rolling is called pronation. Oversupination is a tendency to roll in the opposite direction. Overpronation is the cause of many running injuries such as Achilles tendinitis, plantar fasciitis and knee and hip pain. Prior art attempts to overcome overpronation have included firm heel counters, extended arch supports, filled in midsoles underneath the arch and higher density midsoles usually on the medial side. One prior art shoe incorporated a higher density midsole on the lateral side in order to restrict supination.
It is desirable to provide a midsole construction which limits overpronation and oversupination and which absorbs shock so as to improve comfort and reduce the tendency for fatigue and injury.
It is a general object of the present invention to provide an improved athletic shoe.
It is a further object of the present invention to provide an athletic shoe having a midsole which effectively absorbs shock and limits overpronation of the wearer's foot.
It is a further object of the present invention to provide an athletic shoe which is comfortable during prolonged use and reduces the tendency for fatigue and injury.